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// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package worker provides functionality for running a worker service.
// Its primary operation is to fetch modules from a proxy and write them to the
// database.
package worker
import (
"context"
"errors"
"fmt"
"io"
"net/http"
"reflect"
"strconv"
"strings"
"sync"
"time"
"cloud.google.com/go/errorreporting"
"github.com/go-redis/redis/v7"
"github.com/google/safehtml/template"
"go.opencensus.io/stats"
"go.opencensus.io/stats/view"
"go.opencensus.io/tag"
"go.opencensus.io/trace"
"golang.org/x/pkgsite/internal"
"golang.org/x/pkgsite/internal/config"
"golang.org/x/pkgsite/internal/derrors"
"golang.org/x/pkgsite/internal/index"
"golang.org/x/pkgsite/internal/log"
"golang.org/x/pkgsite/internal/middleware"
"golang.org/x/pkgsite/internal/postgres"
"golang.org/x/pkgsite/internal/proxy"
"golang.org/x/pkgsite/internal/queue"
"golang.org/x/pkgsite/internal/source"
"golang.org/x/pkgsite/internal/stdlib"
)
// Server can be installed to serve the go discovery worker.
type Server struct {
cfg *config.Config
indexClient *index.Client
proxyClient *proxy.Client
sourceClient *source.Client
redisHAClient *redis.Client
redisCacheClient *redis.Client
db *postgres.DB
queue queue.Queue
reportingClient *errorreporting.Client
taskIDChangeInterval time.Duration
templates map[string]*template.Template
staticPath template.TrustedSource
getExperiments func() []*internal.Experiment
}
// ServerConfig contains everything needed by a Server.
type ServerConfig struct {
DB *postgres.DB
IndexClient *index.Client
ProxyClient *proxy.Client
SourceClient *source.Client
RedisHAClient *redis.Client
RedisCacheClient *redis.Client
Queue queue.Queue
ReportingClient *errorreporting.Client
TaskIDChangeInterval time.Duration
StaticPath template.TrustedSource
GetExperiments func() []*internal.Experiment
}
const (
indexTemplate = "index.tmpl"
versionsTemplate = "versions.tmpl"
)
// NewServer creates a new Server with the given dependencies.
func NewServer(cfg *config.Config, scfg ServerConfig) (_ *Server, err error) {
defer derrors.Wrap(&err, "NewServer(db, %+v)", scfg)
t1, err := parseTemplate(scfg.StaticPath, template.TrustedSourceFromConstant(indexTemplate))
if err != nil {
return nil, err
}
t2, err := parseTemplate(scfg.StaticPath, template.TrustedSourceFromConstant(versionsTemplate))
if err != nil {
return nil, err
}
templates := map[string]*template.Template{
indexTemplate: t1,
versionsTemplate: t2,
}
return &Server{
cfg: cfg,
db: scfg.DB,
indexClient: scfg.IndexClient,
proxyClient: scfg.ProxyClient,
sourceClient: scfg.SourceClient,
redisHAClient: scfg.RedisHAClient,
redisCacheClient: scfg.RedisCacheClient,
queue: scfg.Queue,
reportingClient: scfg.ReportingClient,
taskIDChangeInterval: scfg.TaskIDChangeInterval,
templates: templates,
staticPath: scfg.StaticPath,
getExperiments: scfg.GetExperiments,
}, nil
}
// Install registers server routes using the given handler registration func.
func (s *Server) Install(handle func(string, http.Handler)) {
// rmw wires in error reporting to the handler. It is configured here, in
// Install, because not every handler should have error reporting.
rmw := middleware.Identity()
if s.reportingClient != nil {
rmw = middleware.ErrorReporting(s.reportingClient.Report)
}
// scheduled: poll polls the Module Index for new modules
// that have been published and inserts that metadata into
// module_version_states.
// This endpoint is intended to be invoked periodically by a scheduler.
// See the note about duplicate tasks for "/enqueue" below.
handle("/poll", rmw(s.errorHandler(s.handlePollIndex)))
// scheduled: update-imported-by-count update the imported_by_count for
// packages in search_documents where imported_by_count_updated_at is null
// or imported_by_count_updated_at < version_updated_at.
// This endpoint is intended to be invoked periodically by a scheduler.
handle("/update-imported-by-count", rmw(s.errorHandler(s.handleUpdateImportedByCount)))
// scheduled: download search document data and update the redis sorted
// set(s) used in auto-completion.
handle("/update-redis-indexes", rmw(s.errorHandler(s.handleUpdateRedisIndexes)))
// task-queue: fetch fetches a module version from the Module Mirror, and
// processes the contents, and inserts it into the database. If a fetch
// request fails for any reason other than an http.StatusInternalServerError,
// it will return an http.StatusOK so that the task queue does not retry
// fetching module versions that have a terminal error.
// This endpoint is intended to be invoked by a task queue with semantics like
// Google Cloud Task Queues.
handle("/fetch/", http.StripPrefix("/fetch", rmw(http.HandlerFunc(s.handleFetch))))
// scheduled: enqueue queries the module_version_states table for the next
// batch of module versions to process, and enqueues them for processing.
// Normally this will not cause duplicate processing, because Cloud Tasks
// are de-duplicated. That does not apply after a task has been finished or
// deleted for Server.taskIDChangeInterval (see
// https://cloud.google.com/tasks/docs/reference/rpc/google.cloud.tasks.v2#createtaskrequest,
// under "Task De-duplication"). If you cannot wait, you can force
// duplicate tasks by providing any string as the "suffix" query parameter.
handle("/enqueue", rmw(s.errorHandler(s.handleEnqueue)))
// TODO: remove after /queue is in production and the scheduler jobs have been changed.
// scheduled: requeue queries the module_version_states table for the next
// batch of module versions to process, and enqueues them for processing.
// Normally this will not cause duplicate processing, because Cloud Tasks
// are de-duplicated. That does not apply after a task has been finished or
// deleted for Server.taskIDChangeInterval (see
// https://cloud.google.com/tasks/docs/reference/rpc/google.cloud.tasks.v2#createtaskrequest,
// under "Task De-duplication"). If you cannot wait, you can force
// duplicate tasks by providing any string as the "suffix" query parameter.
handle("/requeue", rmw(s.errorHandler(s.handleEnqueue)))
// manual: reprocess sets a reprocess status for all records in the
// module_version_states table that were processed by an app_version that
// occurred after the provided app_version param, so that they will be
// scheduled for reprocessing the next time a request to /enqueue is made.
// If a status param is provided only module versions with that status will
// be reprocessed.
handle("/reprocess", rmw(s.errorHandler(s.handleReprocess)))
// manual: populate-stdlib inserts all modules of the Go standard
// library into the tasks queue to be processed and inserted into the
// database. handlePopulateStdLib should be updated whenever a new
// version of Go is released.
// see the comments on duplicate tasks for "/requeue", above.
handle("/populate-stdlib", rmw(s.errorHandler(s.handlePopulateStdLib)))
// manual: populate-search-documents repopulates every row in the
// search_documents table that was last updated before the time in the
// "before" query parameter.
handle("/repopulate-search-documents", rmw(s.errorHandler(s.handleRepopulateSearchDocuments)))
// manual: clear-cache clears the redis cache.
handle("/clear-cache", rmw(s.errorHandler(s.clearCache)))
// manual: delete the specified module version.
handle("/delete/", http.StripPrefix("/delete", rmw(s.errorHandler(s.handleDelete))))
handle("/static/", http.StripPrefix("/static/", http.FileServer(http.Dir(s.staticPath.String()))))
// returns an HTML page displaying information about recent versions that were processed.
handle("/versions", http.HandlerFunc(s.handleHTMLPage(s.doVersionsPage)))
// Health check.
handle("/healthz", http.HandlerFunc(s.handleHealthCheck))
// returns an HTML page displaying the homepage.
handle("/", http.HandlerFunc(s.handleHTMLPage(s.doIndexPage)))
}
// handleUpdateImportedByCount updates imported_by_count for all packages.
func (s *Server) handleUpdateImportedByCount(w http.ResponseWriter, r *http.Request) error {
n, err := s.db.UpdateSearchDocumentsImportedByCount(r.Context())
if err != nil {
return err
}
fmt.Fprintf(w, "updated %d packages", n)
return nil
}
// handleRepopulateSearchDocuments repopulates every row in the search_documents table
// that was last updated before the given time.
func (s *Server) handleRepopulateSearchDocuments(w http.ResponseWriter, r *http.Request) error {
limit := parseLimitParam(r, 100)
beforeParam := r.FormValue("before")
if beforeParam == "" {
return &serverError{
http.StatusBadRequest,
errors.New("must provide 'before' query param as an RFC3339 datetime"),
}
}
before, err := time.Parse(time.RFC3339, beforeParam)
if err != nil {
return &serverError{http.StatusBadRequest, err}
}
ctx := r.Context()
log.Infof(ctx, "Repopulating search documents for %d packages", limit)
sdargs, err := s.db.GetPackagesForSearchDocumentUpsert(ctx, before, limit)
if err != nil {
return err
}
for _, args := range sdargs {
if err := postgres.UpsertSearchDocument(ctx, s.db.Underlying(), args); err != nil {
return err
}
}
return nil
}
// handleFetch executes a fetch request and returns a http.StatusOK if the
// status is not http.StatusInternalServerError, so that the task queue does
// not retry fetching module versions that have a terminal error.
func (s *Server) handleFetch(w http.ResponseWriter, r *http.Request) {
if r.URL.Path == "/" {
w.Header().Set("Content-Type", "text/html; charset=utf-8")
fmt.Fprintf(w, "<h1>Hello, Go Discovery Fetch Service!</h1>")
fmt.Fprintf(w, `<p><a href="/fetch/rsc.io/quote/@v/v1.0.0">Fetch an example module</a></p>`)
return
}
if r.URL.Path == "/favicon.ico" {
return
}
msg, code := s.doFetch(r)
if code == http.StatusInternalServerError || code == http.StatusServiceUnavailable {
log.Infof(r.Context(), "doFetch of %s returned %d; returning that code to retry task", r.URL.Path, code)
http.Error(w, http.StatusText(code), code)
return
}
if code/100 != 2 {
log.Infof(r.Context(), "doFetch of %s returned code %d; returning OK to avoid retry", r.URL.Path, code)
}
w.Header().Set("Content-Type", "text/plain; charset=utf-8")
if code/100 == 2 {
log.Info(r.Context(), msg)
fmt.Fprintln(w, msg)
}
fmt.Fprintln(w, http.StatusText(code))
}
// doFetch executes a fetch request and returns the msg and status.
func (s *Server) doFetch(r *http.Request) (string, int) {
modulePath, version, err := parseModulePathAndVersion(r.URL.Path)
if err != nil {
return err.Error(), http.StatusBadRequest
}
code, err := FetchAndUpdateState(r.Context(), modulePath, version, s.proxyClient, s.sourceClient, s.db, s.cfg.AppVersionLabel())
if err != nil {
return err.Error(), code
}
return fmt.Sprintf("fetched and updated %s@%s", modulePath, version), code
}
// parseModulePathAndVersion returns the module and version specified by p. p
// is assumed to have either of the following two structures:
// - <module>/@v/<version>
// - <module>/@latest
// (this is symmetric with the proxy url scheme)
func parseModulePathAndVersion(requestPath string) (string, string, error) {
p := strings.TrimPrefix(requestPath, "/")
if strings.HasSuffix(p, "/@latest") {
modulePath := strings.TrimSuffix(p, "/@latest")
if modulePath == "" {
return "", "", fmt.Errorf("invalid module path: %q", modulePath)
}
return modulePath, internal.LatestVersion, nil
}
parts := strings.Split(p, "/@v/")
if len(parts) != 2 {
return "", "", fmt.Errorf("invalid path: %q", requestPath)
}
if parts[0] == "" || parts[1] == "" {
return "", "", fmt.Errorf("invalid path: %q", requestPath)
}
return parts[0], parts[1], nil
}
func (s *Server) handlePollIndex(w http.ResponseWriter, r *http.Request) (err error) {
defer derrors.Wrap(&err, "handlePollIndex(%q)", r.URL.Path)
ctx := r.Context()
limit := parseLimitParam(r, 10)
since, err := s.db.LatestIndexTimestamp(ctx)
if err != nil {
return err
}
modules, err := s.indexClient.GetVersions(ctx, since, limit)
if err != nil {
return err
}
if err := s.db.InsertIndexVersions(ctx, modules); err != nil {
return err
}
log.Infof(ctx, "Inserted %d modules from the index", len(modules))
return nil
}
var (
// keyEnqueueStatus is a census tag used to keep track of the status
// of the modules being enqueued.
keyEnqueueStatus = tag.MustNewKey("enqueue.status")
enqueueStatus = stats.Int64(
"go-discovery/worker_enqueue_count",
"The status of a module version enqueued to Cloud Tasks.",
stats.UnitDimensionless,
)
// EnqueueResponseCount counts worker enqueue responses by response type.
EnqueueResponseCount = &view.View{
Name: "go-discovery/worker-enqueue/count",
Measure: enqueueStatus,
Aggregation: view.Count(),
Description: "Worker enqueue request count",
TagKeys: []tag.Key{keyEnqueueStatus},
}
)
// handleEnqueue queries the module_version_states table for the next batch of
// module versions to process, and enqueues them for processing. Note that this
// may cause duplicate processing.
func (s *Server) handleEnqueue(w http.ResponseWriter, r *http.Request) (err error) {
defer derrors.Wrap(&err, "handleEnqueue(%q)", r.URL.Path)
ctx := r.Context()
limit := parseLimitParam(r, 10)
suffixParam := r.FormValue("suffix") // append to task name to avoid deduplication
span := trace.FromContext(r.Context())
span.Annotate([]trace.Attribute{trace.Int64Attribute("limit", int64(limit))}, "processed limit")
modules, err := s.db.GetNextModulesToFetch(ctx, limit)
if err != nil {
return err
}
span.Annotate([]trace.Attribute{trace.Int64Attribute("modules to fetch", int64(len(modules)))}, "processed limit")
w.Header().Set("Content-Type", "text/plain")
log.Infof(ctx, "Scheduling modules to be fetched: queuing %d modules", len(modules))
// Enqueue concurrently, because sequentially takes a while.
const concurrentEnqueues = 10
var (
mu sync.Mutex
nEnqueued, nErrors int
)
sem := make(chan struct{}, concurrentEnqueues)
for _, m := range modules {
m := m
sem <- struct{}{}
go func() {
defer func() { <-sem }()
enqueued, err := s.queue.ScheduleFetch(ctx, m.ModulePath, m.Version, suffixParam, s.taskIDChangeInterval)
mu.Lock()
if err != nil {
log.Errorf(ctx, "enqueuing: %v", err)
nErrors++
} else if enqueued {
nEnqueued++
stats.RecordWithTags(r.Context(),
[]tag.Mutator{tag.Upsert(keyEnqueueStatus, strconv.Itoa(m.Status))},
enqueueStatus.M(int64(m.Status)))
}
mu.Unlock()
}()
}
// Wait for goroutines to finish.
for i := 0; i < concurrentEnqueues; i++ {
sem <- struct{}{}
}
log.Infof(ctx, "Successfully scheduled modules to be fetched: %d modules enqueued, %d errors", nEnqueued, nErrors)
return nil
}
// handleHTMLPage returns an HTML page using a template from s.templates.
func (s *Server) handleHTMLPage(f func(w http.ResponseWriter, r *http.Request) error) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
if err := f(w, r); err != nil {
log.Errorf(r.Context(), "handleHTMLPage", err)
http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
}
}
}
func (s *Server) handlePopulateStdLib(w http.ResponseWriter, r *http.Request) error {
msg, err := s.doPopulateStdLib(r.Context(), r.FormValue("suffix"))
w.Header().Set("Content-Type", "text/plain; charset=utf-8")
if err != nil {
return fmt.Errorf("handlePopulateStdLib: %v", err)
}
log.Infof(r.Context(), "handlePopulateStdLib: %s", msg)
_, _ = io.WriteString(w, msg)
return nil
}
func (s *Server) doPopulateStdLib(ctx context.Context, suffix string) (string, error) {
versions, err := stdlib.Versions()
if err != nil {
return "", err
}
for _, v := range versions {
if _, err := s.queue.ScheduleFetch(ctx, stdlib.ModulePath, v, suffix, s.taskIDChangeInterval); err != nil {
return "", fmt.Errorf("error scheduling fetch for %s: %w", v, err)
}
}
return fmt.Sprintf("Scheduling modules to be fetched: %s.\n", strings.Join(versions, ", ")), nil
}
func (s *Server) handleReprocess(w http.ResponseWriter, r *http.Request) error {
appVersion := r.FormValue("app_version")
if appVersion == "" {
return &serverError{http.StatusBadRequest, errors.New("app_version was not specified")}
}
if err := config.ValidateAppVersion(appVersion); err != nil {
return &serverError{http.StatusBadRequest, fmt.Errorf("config.ValidateAppVersion(%q): %v", appVersion, err)}
}
status := r.FormValue("status")
if status != "" {
code, err := strconv.Atoi(status)
if err != nil {
return &serverError{http.StatusBadRequest, fmt.Errorf("status is invalid: %q", status)}
}
if err := s.db.UpdateModuleVersionStatesWithStatus(r.Context(), code, appVersion); err != nil {
return err
}
fmt.Fprintf(w, "Scheduled modules to be reprocessed for appVersion > %q and status = %d.", appVersion, code)
return nil
}
if err := s.db.UpdateModuleVersionStatesForReprocessing(r.Context(), appVersion); err != nil {
return err
}
fmt.Fprintf(w, "Scheduled modules to be reprocessed for appVersion > %q.", appVersion)
return nil
}
func (s *Server) clearCache(w http.ResponseWriter, r *http.Request) error {
if s.redisCacheClient == nil {
return errors.New("redis cache client is not configured")
}
status := s.redisCacheClient.FlushAll()
if status.Err() != nil {
return status.Err()
}
fmt.Fprint(w, "Cache cleared.")
return nil
}
// handleDelete deletes the specified module version.
func (s *Server) handleDelete(w http.ResponseWriter, r *http.Request) error {
modulePath, version, err := parseModulePathAndVersion(r.URL.Path)
if err != nil {
return &serverError{http.StatusBadRequest, err}
}
if err := s.db.DeleteModule(r.Context(), modulePath, version); err != nil {
return &serverError{http.StatusInternalServerError, err}
}
fmt.Fprintf(w, "Deleted %s@%s", modulePath, version)
return nil
}
func (s *Server) handleHealthCheck(w http.ResponseWriter, r *http.Request) {
if err := s.db.Underlying().Ping(); err != nil {
http.Error(w, fmt.Sprintf("DB ping failed: %v", err), http.StatusInternalServerError)
return
}
fmt.Fprintln(w, "OK")
}
// Parse the template for the status page.
func parseTemplate(staticPath, filename template.TrustedSource) (*template.Template, error) {
if staticPath.String() == "" {
return nil, nil
}
templatePath := template.TrustedSourceJoin(staticPath, template.TrustedSourceFromConstant("html/worker"), filename)
return template.New(filename.String()).Funcs(template.FuncMap{
"truncate": truncate,
"timefmt": formatTime,
"bytesToMi": bytesToMi,
"pct": percentage,
"timeSince": func(t time.Time) time.Duration {
return time.Since(t).Round(time.Second)
},
"timeSub": func(t1, t2 time.Time) time.Duration {
return t1.Sub(t2).Round(time.Second)
},
}).ParseFilesFromTrustedSources(templatePath)
}
func truncate(length int, text *string) *string {
if text == nil {
return nil
}
if len(*text) <= length {
return text
}
s := (*text)[:length] + "..."
return &s
}
var locNewYork *time.Location
func init() {
var err error
locNewYork, err = time.LoadLocation("America/New_York")
if err != nil {
log.Fatalf(context.Background(), "time.LoadLocation: %v", err)
}
}
func formatTime(t *time.Time) string {
if t == nil {
return "Never"
}
return t.In(locNewYork).Format("2006-01-02 15:04:05")
}
// bytesToMi converts an integral value of bytes into mebibytes.
func bytesToMi(b uint64) uint64 {
return b / (1024 * 1024)
}
// percentage computes the truncated percentage of x/y.
// It returns 0 if y is 0.
// x and y can be any int or uint type.
func percentage(x, y interface{}) int {
denom := toUint64(y)
if denom == 0 {
return 0
}
return int(toUint64(x) * 100 / denom)
}
func toUint64(n interface{}) uint64 {
v := reflect.ValueOf(n)
switch v.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return uint64(v.Int())
default: // assume uint
return v.Uint()
}
}
// parseLimitParam parses the query parameter with name as in integer. If the
// parameter is missing or there is a parse error, it is logged and the default
// value is returned.
func parseLimitParam(r *http.Request, defaultValue int) int {
const name = "limit"
param := r.FormValue(name)
if param == "" {
return defaultValue
}
val, err := strconv.Atoi(param)
if err != nil {
log.Errorf(r.Context(), "parsing query parameter %q: %v", name, err)
return defaultValue
}
return val
}
type serverError struct {
status int // HTTP status code
err error // wrapped error
}
func (s *serverError) Error() string {
return fmt.Sprintf("%d (%s): %v", s.status, http.StatusText(s.status), s.err)
}
// errorHandler converts a function that returns an error into an http.HandlerFunc.
func (s *Server) errorHandler(f func(w http.ResponseWriter, r *http.Request) error) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
if err := f(w, r); err != nil {
s.serveError(w, r, err)
}
}
}
func (s *Server) serveError(w http.ResponseWriter, r *http.Request, err error) {
ctx := r.Context()
serr, ok := err.(*serverError)
if !ok {
serr = &serverError{status: http.StatusInternalServerError, err: err}
}
if serr.status == http.StatusInternalServerError {
log.Error(ctx, serr.err)
} else {
log.Infof(ctx, "returning %d (%s) for error %v", serr.status, http.StatusText(serr.status), err)
}
http.Error(w, serr.err.Error(), serr.status)
}